Step 1: Preheat your oven to 350°F (175°C) and grease your loaf pan with non-stick spray or line it with parchment paper for easy removal later.

Step 2: In a medium mixing bowl, whisk together the flour, cocoa powder, baking powder, and salt. Set aside.

Step 3: In a large bowl, mix the granulated sugar, brown sugar, eggs, melted butter, and vanilla extract until smooth and well combined.

Step 4: Gradually add the dry ingredients to the wet ingredients and stir until just combined. Be careful not to overmix.

Step 5: Pour in the hot fudge sauce and stir gently until the fudge is fully incorporated into the batter. Optionally, fold in the chocolate chips.

Step 6: Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Step 7: Bake for 45-50 minutes, or until a toothpick inserted into the center comes out clean with a few crumbs. Let the bread cool in the pan for 10 minutes, then transfer it to a cooling rack.